Improvement in saw-grinding machines



H'. DISSTON.

Saw-Grinding Machines.

N0.156,989. Patented Nov. 17, 1874.-

UNITED STATES PATENT QFFICE.

HENRY DISSTON, OF PHILADELPHIA, PENNSYLVANIA.

I IMPROVEMENT lN SAW-GRINDING MACHINES.

Specification forming part of Letters Patent No. 156,989, dated November 17, 1874; application filed August 7, 1874.

To all whom it may concern:

Be it known that I, HENRY DISSTQN, of Philadelphia, Pennsylvania, have invented an Improved Saw-Grinding Machine, of which the following is a specification:

The object of my invention is to impart to circular-saw blades, with uniformity and rapidity, the desired taper; and this object I attain by the combination of a rotating table, A, on which the blade is placed, with grindstones B B on a shaft, D, arranged to reciprocate in its bearings and to be sprung, by a rod, E, or other suitable device, so much out of line that the blade must necessarily be ground thinner at the edges than in the middle, or thinner in the middle than at the edges, according as the said shaft is sprung upward or downward, all as shown in the front elevation, Figure 1, and plan view, Fig. 2, of the accompanying drawing.

G is the bed of the machine, on which a table, A, is caused to rotate by any suitable system of gearing. H and H are two frames or stands secured to the bed G, one on each side of the table A, and connected together by bars 0 and f, and to guides in front of each frame is adapted a sliding bearing, a, (shown in the detached view, Fig. 3,) for the shaft D, each bearing being controlled by a vertical screw, I, and the two screws being geared together by worms and worm-wheels and a horizontal shaft, J, in a manner too clearly shown in the drawing to need detailed description. To the shaft D are secured two sets of grindstones, B B, and between the latter the shaft is embraced by a bearing, 12, at the lower end of a screw-rod, E, which is guided by a projection, d, on the bar e. The threaded portion of the rod E passes through a nut, M, which is arranged to turn in a bearing, h, on the cross-bar f, so that, by turning a hand-wheel, 2', on the nut, the screw-rod, and with it the middle portion of the shaft D, can be raised or lowered at pleasure. The nut M for controlling the screw-shaft E can also be operated from the shaft J by a bevel-wheel, n, on the latter, gearing into a like wheel, n, on a shaft, 19, which carries a worm, q, gearing into a worm-wheel, w, on the nut M. This gearing is so arranged, in respect to that by which motion is communicated from the shaft J to the screws H and H, that, on turning the shaft J, the three bearings a a and b of the shaft D must be raised or lowered simultaneously.

It will be understood that'this simultaneous raising or lowering of the three bearings by operating the shaft J can only be accomplished when the worm-wheel w is fast on the nut M, and that, whenever it becomes necessary to raise or lower the middle bearing 11 independently of the outer bearings, the wormwheel w must be loose on the said nut; hence this worm-wheel must be provided with a setscrew or equivalent device, by which it can be readily connected to or disconnected from the nut.

To the shaft D is secured a scroll-cam, P, into the groove of which projects a pin, t, on a bracket projecting from the frame H H, so that, as the shaft rotates, it will reciprocate in its bearings.

As long as the shaft D remains straight the stones B B will impart a perfectly level surface to the saw-blade on the table A; but, if the shaft D be sprung out of line by raising the middle bearing or lowering the two outer bearings, such a beveled surface must necessarily be imparted to the blade that the latter must diminish invthickness from the middle to the edges, the taper imparted to the blade depending upon the extent to which the shaft maybe sprung out of line. If the blade is to be thinner in the middle than at the edges, the middle bearing is lowered instead of raised, so as to spring the shaft downward in the center.

If desired, swivel-bearings may be substi- In a circnlar-saw-grinding machine, the combination of a rotating table for receiving the saw-blade, two grindstones, arranged above the table on opposite sides of the center thereof, and. devices for imparting to said stones, or either of them, the desired inclination, substantially as set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

HENRY DISSTON.

Witnesses:

A. H. SHOEMAKER, HUBERT HoWsoN. 

